The blacktop has lighter internals which might be also weaker, but it's kind of quicker. No damage if you are not undertaking any major mods, but any pressured induction and you will be needing to uprate the blacktops internals. The 5 valve head is Toyota's bonus for the 4AG following https://louistphav.mybloglicious.com/47945459/little-known-facts-about-toyota-4age-blacktop-engine-for-sale